Danger can lurk onboard cruise ships too, according to critics, especially because of heavy drinking and the cut-loose atmosphere of some ships. Rates for sexual assault on cruise ships seem to be about 50% higher than on land, according to Ross Klein, a professor at Memorial University in Newfoundland, who studies the cruise industry.

The cruise industry says such reports are overblown. A spokesman for the Cruise Lines International Association directed questions about onboard crime to James Alan Fox, a Northeastern University criminologist whose research it has previously sponsored. Fox says that while he wasn’t familiar enough with Klein’s work to evaluate his specific findings, Fox told us that his own research suggests ships have lower crime rates than other popular tourist destinations like Las Vegas or Orlando. One reason is crowds, cameras and security staff. Another is cruising’s bourgeois demographics. “There are no high-crime areas on cruise ships,” he says.